The Key Ingredients That Set Japan-Style Mashed Potatoes Apart

The Japanese style of mashed potatoes typically contains none of the same ingredients that are found in the recipes for the American version. This means there's usually zero sour cream, chicken broth, butter, cream cheese, or milk. Instead, you'll likely see rice vinegar and kewpie mayo, two staples in Japanese cuisine. Japanese rice vinegar is made from fermented rice and has a lighter taste than the more American-style condiments, and kewpie mayo is tangier and contains more umami flavor than our versions here in the States. 

When you swap out American mayo and add these two Japanese ingredients to mashed potatoes, you get a lighter, tangier version of the dish. Instead of the American-style recipes, which tend to be a little more one-note, Japanese-style mashed spuds have a nice balance of tart and rich flavors. You may also get slight notes of sweetness when you take a bite, thanks to the rice vinegar. But due to the egg yolk-only mayo involved, Japanese mashed potatoes are still thick, creamy, and delicious.

In Japan, mashed potatoes are often served in a dish that somewhat resembles American-style potato salad. But unlike in the U.S., where our spuds are typically boiled and chopped in a potato salad, the Japanese-style version involves mashing them almost all the way, leaving just a little chunkiness. Because American-style dishes generally want to retain the shape and texture of the potatoes, we tend to go for waxy varieties like red ones. 

However, Japanese recipes favor starchy spuds that make for a rich, creamy salad and are more likely to fall apart, like russet and Idaho potatoes. The mashed spuds tend to include kewpie mayo and rice vinegar, as we've covered, but the rest of the ingredients in the salad vary, much like with American-style recipes. You'll generally see a variety of colorful veggies and proteins — some recipes call for boiling the spuds with carrots to enhance their sweetness and many include cucumber, onions, and corn on their ingredient list. 

You'll also commonly find chopped hard-boiled eggs, along with ham or Japanese sausage. Mustard and scallions are sometimes added for additional flavoring too. While the mashed spuds make a creamy base, the other additions provide a variety of flavors and textures that come together to make Japanese-style potato salad a complex and tasty dish.